Data Storage Technique

1. A method for storing a computer file in a memory, the method comprising, storing each of a plurality of chunks in a respective bag, each chunk being a transformed version of a respective segment of the file that was subjected to a particular transformation, and each bag comprising a portion of contiguous space in the memory associated with a respective one of the segments, said each bag having a gap of unused memory space that can accommodate increases in the size of chunks stored in said each bag, reading a particular one of the chunks from the memory, subjecting the particular one of the chunks to a reverse transformation to recover the respective segment, altering the recovered segment and subjecting the altered segment to said particular transformation, the altering being such that the resulting chunk is larger than the chunk that was read from memory, and storing said resulting chunk in the bag associated with the altered segment, this storing including storing at least a portion of said resulting chunk in the associated bag's gap.

2. The method of claim 1 wherein the particular transformation is data compression.

3. The method of claim 1 wherein the particular transformation is data encryption.

4. The method of claim 1 wherein the size of each said bag is a function of the size of the chunk initially stored therein.

5. The method of claim 4 wherein the size of said chunk initially stored therein is C and wherein said size of said bag is C multiplied by a bag factor f≧1.

6. A method of storing transformed files of a computer system on a slow memory for random access to data comprising the transformed files, said method comprising: dividing each of the transformed files into data segments; converting each of the data segments into data chunks in accordance with a predetermined transformation; and storing each of the chunks in a bag of slow memory space wherein each bag further comprises a gap of unused slow memory space that accommodates increases in chunk size that results when data is written in a corresponding segment.

7. The method as recited in claim 6 wherein the transformation is data compression.

8. The method as recited in claim 6 wherein the transformation is data encryption.

9. A computer program product, comprising a computer usable medium having a computer readable program code embodied therein, said computer readable program code adapted to be executed to implement a method of storing transformed files of a computer system on a slow memory for random access to data comprising the transformed files, the method comprising dividing each of the transformed files into data segments; converting each of the data segments into data chunks in accordance with a predetermined transformation; and storing each of the chunks in a bag of slow memory space wherein each bag further comprises a gap of unused slow memory space that accommodates increases in chunk size that results when data is written in a corresponding segment.